BANGOR, Maine — In a 6-3 vote Monday night, the City Council passed an ordinance that bans some sex offenders from moving to within 750 feet of a publicly owned property frequented by children.

When the council first voted on the ordinance 28 months ago, Councilor David Nealley was the only councilor to vote in favor of the ordinance. This time around, he was joined by Councilors Joe Baldacci, Pauline Civiello, James Gallant, Charlie Longo, David Nealley and Benjamin Sprague.

The residency restriction applies to individuals convicted of Class A, B or C sex offenses committed against a child under age 14. Offenders in that category who live within a 750-foot boundary won’t be required to move. However, if they did move, their residence would have to be outside the restricted zone, and they could not move back into a restricted area. That’s the most restrictive ordinance allowed under Maine law.

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Bangor residents who spoke at committee and council meetings had voiced support for the ordinance.

David Green of Dunning Boulevard, who helped revive the proposed ordinance, said it would “make Bangor a less attractive destination for sex offenders,” pointing out that 21 of Bangor’s 141 registered offender registrants are from out of state and more than 60 percent of them are from outside Penobscot County.

The effectiveness of such ordinances across the country has been called into question in studies in Iowa, Colorado, California, Florida and other states. Most studies argue that the restrictions don’t have any effect, and some say they create a false sense of security in communities and decrease safety.

Councilors who voted against the ordinance, both in 2010 and again in 2013, argued that the proposal was nothing more than a feel-good ordinance.

In Minnesota, the state’s Department of Corrections conducted studies in 2003 and 2007 and found that there was no evidence that residential proximity to schools or parks affected recidivism rates, as people who offend tend to do so away from their own neighborhoods. The department’s research also found that pushing high-risk sex offenders to rural or suburban areas resulted in less access to services and supervision.

National studies indicate that more than 90 percent of child sexual assaults are perpetrated by someone who knows the child, oftentimes in the offender’s or victim’s home, according to the U.S. Department of Justice. Other studies indicate that sexual predators seldom offend in their own neighborhoods and target children away from their homes.

Shawn Yardley, the city’s director of health and community services, said during Monday’s meeting that while the ordinance seemed to be “well intended,” it could give parents and the public a false sense of security by indicating to parents that it’s safe to send their kids to a park because there aren’t any sex offenders in the area. Councilors Blanchette, Durgin and Hawes have echoed those same concerns, pointing at the ineffectiveness outlined in the studies.

Even some councilors who voted in favor of the ordinance Monday conceded it might not have tangible effects, but argued that it sent a message and took a step toward solving growing problems in the city.

Nealley and Sprague each said they “struggled” with their positions on the ordinance based on questions of efficacy.

“Probably they’re right,” Nealley said of the case studies’ findings, but he added that he didn’t believe doing nothing was the right move for the city.

Gallant pointed out that one of the studies states that “only” 7 percent of child sexual assaults are perpetrated by strangers. He said the use of “only” was troubling, as was the 7 percent figure.

“Even if we could save 7 percent — only 7 percent — it would be a good idea,” Gallant said.

Other councilors said that if the ordinance prevented one incidence of sexual abuse of a child, it would be worthwhile.

Also during Monday’s meeting, the council voted to place a 180-day moratorium on quarries in the city after year-old concerns about noise and ailing property values suddenly re-emerged during committee meetings in March. Councilors said they would like to come to a solution well before the 180 days are up.